Heretofore various machines have been devised for use in reducing fibrous material, such as wood, to chip form. However, to the best of my knowledge, these prior machines have suffered from one or more disadvantages including for instance the amount of physical labor normally required to mount/dismount/resharpen knife blades or other cutting elements employed in such machines; and the inability of such machines to be adjusted or the difficulty with which such machines may be adjusted to produce varying sizes of chips.